RADIATION DESIGN AND CONTROL FEATURES OF A HOSPITAL ROOM FOR A LOW-DOSE RATE REMOTE AFTERLOADING UNIT

We have renovated, and used for four years, a small 3.4 m x 4.3 m conv entional patient second floor hospital room to accommodate a low dose rate remote afterloading unit containing 13 GBq (0.35 Ci) of Cs-137. S upplemental room shielding consists of a power assisted door (536 kg, 1.7 cm thickness of lead), 1.3 cm lead wall shielding at selected wall locations and on a projector shield beneath the bed, and 0.6 cm of le ad over the floor above. Radiation control features consisted of a roo m interior radiation detector independent of the remote afterloading u nit, a redundant patient/nurse communication system, a remote control system, a door interlock system to insert and retract the radioactive pellets, and a visible and audible status indicator system located at a nearby nurses' work station. Renovation costs (in 1990 dollars) were $383 per square foot; total project costs were $187,000. Nursing pers onnel radiation exposure was reduced from about 6 mu Sv (mg Ra eq)(-1) (0.6 mrem (mg Ra eq)(-1)) to about 0.7 mu Sv (mg Ra eq)(-1) (0.07 mre m (mg Ra eq)(-1)), almost a tenfold reduction.